/Engine/Plugins/Experimental/MeshModelingToolsetExp/Source/MeshModelingToolsExp/Public/MeshVertexPaintTool.h
Fill all Vertex Colors with the current Erase color. Current Channel Filter still applies.
[UFUNCTION](Programming/UnrealArchitecture/Reference/Functions)(CallInEditor, Category=QuickActions, Meta=(DisplayPriority=13)) void EraseAll()